Extreme ultraviolet light generation apparatus, target collection device, and target collection method

Abstract

A target collection device may include a collection container having an opening through which a target material is collected into the collection container, and a temperature adjuster configured to adjust a temperature of the collection container to a temperature that is equal to or higher than a melting point of the target material. The target collection device may be part of an extreme ultraviolet light generation apparatus. Methods of target collection are also provided.

What is claimed is: 
     
         1 . A target collection device, comprising:
 a collection container having an opening through which a target material is collected into the collection container; and   a temperature adjuster configured to adjust a temperature of the collection container to a temperature that is equal to or higher than a melting point of the target material.   
     
     
         2 . The target collection device according to  claim 1 , further comprising a capacity adjuster configured to discharge the target material from the collection container so that a fluid level of the target material in the collection container is retained within a predetermined range. 
     
     
         3 . The target collection device according to  claim 2 , wherein:
 the collection container includes a side wall having a through-hole formed therein and a bottom;   the capacity adjuster includes a discharge pipe connected to the side wall of the collection container at a periphery of the through-hole; and   the temperature adjuster includes a pipe temperature adjuster configured to adjust a temperature of the discharge pipe to a temperature that is equal to or higher than the melting point of the target material.   
     
     
         4 . The target collection device according to  claim 2 , further comprising a fluid level controller, wherein:
 the collection container includes a side wall and a bottom having a through-hole formed therein;   the capacity adjuster includes a discharge pipe connected to the bottom of the collection container at a periphery of the through-hole;   the temperature adjuster includes a pipe temperature adjuster configured to adjust a temperature of the discharge pipe to a temperature that is equal to or higher than the melting point of the target material; and   the fluid level controller includes:
 a flow rate adjuster configured to regulate a flow rate of the target material in the discharge pipe, 
 an upper limit detector configured to send an upper limit signal upon detecting a fluid level of the target material in the collection container exceeding a first predetermined level, 
 a lower limit detector configured to send a lower limit signal upon detecting a fluid level of the target material in the collection container reaching a second predetermine level, and 
 a discharge controller configured to control the flow rate adjuster upon receiving the upper limit signal to discharge the target material from the collection container and control the flow rate adjuster upon receiving the lower limit signal to stop a discharge of the target material from the collection container. 
   
     
     
         5 . The target collection device according to  claim 2 , wherein the capacity adjuster further includes:
 a collection tank into which the target material is discharged from the collection container; and   a supply amount adjuster configured to adjust an amount of the target material to be supplied into the collection container from the collection tank.   
     
     
         6 . An extreme ultraviolet light generation apparatus, comprising:
 a chamber in which extreme ultraviolet light is generated;   a target supply device configured to output a target material into the chamber; and   the target collection device of  claim 1 .   
     
     
         7 . A target collection method, comprising:
 forming a liquid surface of a target material in a collection container for collecting the target material; and   receiving the target material outputted from a target supply device at the liquid surface.   
     
     
         8 . The target collection method according to  claim 7 , further comprising discharging the target material from the collection container so that a fluid level of the target material in the collection container is retained within a predetermined range. 
     
     
         9 . The target collection method according to  claim 8 , wherein:
 the target material is discharged from the collection container through a discharge pipe, and   a temperature of the discharge pipe is adjusted to a temperature that is equal to or higher than a melting point of the target material.   
     
     
         10 . The target collection method according to  claim 9 , wherein:
 a discharge port of the discharge pipe is provided at a predetermined depth in the collection container, and   the target material is discharged from the collection container through the discharge port when a fluid level of the target material exceed a predetermined level.   
     
     
         11 . The target collection method according to  claim 9 , further comprising:
 adjusting a flow rate of the target material in the discharge pipe;   detecting a fluid level of the target material exceeding the predetermined range; and   detecting a fluid level of the target material falling below a predetermined lower limit,   wherein   based on a detection of the fluid level exceeding the predetermined range, the flow rate of the target material is adjusted so that the target material is discharged, and   based on a detection of the fluid level falling below the predetermined lower limit, a discharge of the target material is stopped.   
     
     
         12 . The target collection method according to  claim 9 , wherein the liquid surface is formed by supplying a target material from a container other than the target supply device into the collection container. 
     
     
         13 . The target collection method according to  claim 12 , wherein:
 the target material discharged from the collection container is stored in a collection tank,   the target material stored in the collection tank is supplied into the collection container through the discharge pipe, and   a temperature of the collection tank and a temperature of the discharge pipe are adjusted to a temperature that is equal to or higher than the melting point of the target material.